Method of and apparatus for fabricating metallic strips



Dec. 14, 1965' F. A. MOLELLA METHOD OF AND APPARATUS FOR FABRICATING METALLIC STRIPS Filed Nov. 5, 1961 FIG. 2

FIG. I

INVENTOR. FILBERT A. MOLELLA MZVZ ATTORNEY.

United States Patent 3 222,908 METHDD OF AND APPARATUS FOR FABRI- CATING METALLIC STRIPS Filbert A. Molella, 509 Bronson Road, Syracuse, N.Y. Filed Nov. 3, 1961, Ser. No. 149,892 Claims. (Cl. 72299) This invention relates broadly to metal fabricating. More particularly, this invention relates to the formation of thin, flat metallic strips into certain shapes. Still more particularly, this invention is concerned with apparatus for and a method of forming a thin, elongated metallic strip into a generally curvilinear configuration.

The bending or twisting of a thin, elongated metallic strip into a helical shape having a predetermined pitch poses a formidable problem when the maintenance of critical tolerances is involved. The problem becomes more acute when the strip is composed of material possessing a high degree of ductility. Accordingly, it is the chief object of this invention to provide a method of forming elongated metal strips into a predetermined curvilinear configuration in which the method is especially suited to deform relatively thin strips of ductile material.

Another object of the invention is the provision of a method of forming elongated metallic strips in a generally helical shape wherein said method may be practiced without the need for expensive equipment.

Another object of the invention is the provision of improved apparatus for forming metal strips into curved shapes.

Still another object of the invention is the provision of a novel relation between metal deforming means and a die member for guiding the means into engagement with the metal strip to be fabricated.

The objects of the invention are obtained by the practice of a method of the kind described wherein metal forming means are wound about a metallic strip in tight, intimate engagement therewith so that the strip is enveloped within the adjacent folds of the means and assumes a configuration determined by the shape of the wound member and, thereafter, separating the two parts without disturbing the form of the strip.

Other objects and features of the invention will be apparent upon a consideration of the ensuing specification and drawing in which:

FIGURE 1 is a perspective view of a thin, elongated metallic strip prior to formation into a generally helical configuration;

FIGURE 2 is a perspective view of the strip illustrated in FIGURE 1 after formation into a generally helical configuration in accordance with the teachings of this invention;

FIGURE 3 is an elevational view partly in section showing a novel forming die employed in the process of fabricating a flat, elongated strip into a helical configuration;

FIGURE 4 is an end view of the die illustrated in FIG- URE 3 showing the relation between the various passages provided in the die;

FIGURE 5 is a fragmentary view illustrating the operation of the novel process forming the subject of the invention.

As previously indicated, the invention is concerned with a method of an apparatus for forming an elongated metallic strip into a shape having a predetermined configuration. For the purpose of illustrating the invention only, a presently preferred arrangement will be described. The present invention has been successfully employed for the purpose of forming an elongated metallic strip composed of stainless steel and having a thickness on the order of .005 and a width of .114" into a generally helical shape having a pitch of 5 turns per inch of length.

3,222,908 Patented Dec. 14, 1965 Broadly, the desired shape of the strip is obtained by twisting or winding material deforming means about the strip under circumstances where the strip assumes a configuration determined by the curve or path generated by the means. I have found that a strip of the kind under consideration may be formed into a helical configuration by forcibly winding or twisting a pair of crossed wire-like elements having an outside diameter of .061 and a resistance to deformation sufficient to cause the strip to be enveloped between the wires when the winding is accomplished with one end of the strip engaged between the wire members at their intersection.

To this end a forming die 10 having a generally cylindrical configuration is provided. The die 10 includes a circular passage 12 extending centrally thereof, preferably concentric with the longitudinal axis of the die. One end of passage 12 is enlarged to form an inclined shoulder 14. The passage 12 has a diameter of a size to permit insertion and withdrawal of strip member S without substantial interference to the movement. For example, with the strip member having a width of .113 the passage 12 may have a diameter of .116". In addition to central passage 12, two inclined passages 16 and 18 extend from the side of the die and terminate in openings 20 and 22 in the surface of shoulder 14 and are arranged so that the centers thereof are offset from the central axis of passage 12 in the manner illustrated in FIGURE 4 for a purpose to be later described.

In the practice of the method forming the invention, metal deforming members A and B, shown in the form of wires having the dimensions referred to above, are inserted through passages 16 and 18 from a roll or other supply source. Insertion of wires A and B, occurs in the direction indicated by the arrows on FIGURE 3. The metal deforming members A and B are passed entirely through the passages 16 and 18 so that the free ends thereof extend beyond the end of the die 10 and overlap one another a short distance from their free ends, note FIGURE 3. The inclined passages are preferably arranged so that openings 20 and 22 permit the members A and B to cross one another with a predetermined clearance. With the parts in the position described, the metallic strip S, in the form shown in FIGURE 1, is inserted between the overlapped members A and B and into the passage 12 of the die 10. The clearance referred to above is such that the strip S is accommodated between the wires without undue interference or binding. The members A and B and the strip S are clamped against one another at the locus of engagement with a tool, not shown. With the parts A and B and strip S restrained against separation in this manner, the tool maintaining the parts in engagement is simultaneously rotated and advanced in a direction away from the die. It will be obvious that such movement will wrap the members A and B tightly about the strip while providing for continual movement of the members A and B through the passages 16 and 18, note FIGURE 3. The members A and B, being formed of material having at least as great and preferably greater resistance to deformation as the strip S, will curl the latter into tight, intimate engagement with the wires. Thus the strip will be enveloped between adjacent folds of the alternate wires A and B and assume a corresponding configuration.

The relative movement between the die and clamping tool will continue until the strip S is drawn completely from the die and wrapped tightly between the metal deforming units A and B. The portion of members A and B is engagement with the deformed strip S is severed from the linear portions projecting from the die and the assembled strip and wires removed from the clamping tool. Separation of the wires A and B from the helical strip may be effected in any desired manner. One recommended manner of separating the parts involves dipping them in a bath containing an acid that will attack and consume the metal deforming members A and B without effect on the helical strip S. When the membersA and B are composed of galvanized steel wire, nitric acid will accomplish the desired separation without alfecting the formed strip S when composed of #347 stainless steel.

FIGURE 5 illustrates a practical application of the invention for production work and shows a clamping tool 24 mounted in the headstock of a conventional lathe of the kind used generally in machining metal. The die member may be mounted in suitable supporting structure secured to the usual tool post carriage on the lathe. With the arrangement shown rotary motion is imparted to the tool 24 while the carriage traverses the bed of the lathe to obtain the desired movement of parts A, B and S. Thus the method described may be carried out with conventional machine tool equipment, without requiring expensive revision thereof.

It will be obvious that configurations other than that illustrated may be imparted to metallic strips by varying the shape of the metal deforming members or wires A, B. Other variations will suggest themselves to those skilled in the art without departing from the invention. In developing the die member 10 the openings 20 and 22 are arranged as shown in FIGURE 4 with the center of each offset from opposite sides of the center of the strip by a distance slightly more than the radius of the wire plus one half the thickness of the strip for best results.

While I have described a preferred embodiment of my invention, it will be understood that the invention is not limited thereto but may be embodied within the scope of the following claims.

I claim: 7

1. The method of forming an elongated metallic strip into a predetermined configuration which comprises securing a metal deforming means to a portion of the strip and imparting simultaneous rotary and longitudinal movement to the metal deforming means so that the metal deforming means envelops the metallic strip causing the strip to assume a configuration determined by the path generated by the metal deforming means.

2. The method set forth in claim 1 including the step of separating the member and strip while preserving the configuration imparted to the strip.

3. The method of forming an elongated metallic strip into a generally helical configuration which comprises the steps of supporting first and second metal deforming members for movement through confined passages arranged at a predetermined inclination; advancing the members through the passages until they project beyond the limit of said passages and overlap one another; inserting the strip to be formed between the overlapped members so that the strip extends rearwardly thereof; restraining said members and said strip from separation and advancing and simultaneously rotating the point of restraint so that the metal deforming members are tightly wound about the strip, whereby the strip is enveloped between the members and assumes a configuration defined by the wound members.

4. The method set forth in claim 3 including the step of separating the metal deforming members from the formed strip to preserve the assumed configuration of the strip.

5. The method of forming an elongated metallic strip into a generally helical configuration comprising the steps of Winding metal deforming means about the strip throughout its axial extent so that the metallic strip is enveloped between the individual turns of the means and assumes a shape determined by the pitch of the helix generated by the means; and separating the metal deforming member from the formed strip.

References Cited by the Examiner UNITED STATES PATENTS 445,303 1/1891 Southard 29-549 458,115 8/1891 Thomson 29549 2,377,629 6/1945 Heinemann 153--78 2,427,507 9/ 1947 Powell et al. 29-549 2,628,653 2/1953 Sherman 153-78 2,817,363 12/1957 Penrose 15372 3,055,103 9/1962 Fernberg 29--549 CHARLES W. LANHAM, Primary Examiner. WHITMORE A. WILTZ, Examiner. 

1. THE METHOD OF FORMING AN ELONGATED METALLIC STRIP INTO A PREDETERMINED CONFIGURATION WHICH COMPRISES SECURING A METAL DEFORMING MEANS TO A PORTION OF THE STIP AND IMPARTING SIMULTANEOUS SROTARY AND LONGITUDINAL MOVEMENT TO THE METAL DEFORMIONG MEANS SO THAT THE METAL DEFORMING MEANS ENVELOPS THE METALLIC STRIP CAUSING THE STRIP TO ASSUME A CONFIGURATION DETERMINED BY THE PATH GENERATED BY THE METAL DEFORMING MEANS. 